If you look at the posts above it you can see its about this twitter post:


Where it says these solo miners are lucky, but if you want to know how to see if they are solo mining or not?

You can find that all in the blockchain, lets say the the bitcoin address that receives those bitcoins is a wallet operated by one person.
Or that the wallet is paying out to a lot of users that are mining in a pool, most big pool wallets are known addresses I assume as well.